Environmental Impact of RO Desalination Brine and Sustainable Management Strategies: A Case Study for Iran

The rapid expansion of desalination capacity in arid regions has alleviated freshwater shortages but intensified the challenge of brine disposal. In Iran and other Middle Eastern countries, Reverse Osmosis (RO) desalination plants discharge high-salinity brine (>۷۰,۰۰۰ mg/L TDS) containing heavy metals, antiscalants, and trace organics, which threaten marine ecosystems and soil quality. This study presents a semi-industrial RO–Zero Liquid Discharge (ZLD) pilot system for brine minimization and selective resource recovery in the southern petrochemical region of Iran. The pilot (۵ m³/h) integrates chemical softening, two-stage RO, and crystallization, achieving ۹۵% total water recovery and notable reductions in salinity and chemical oxygen demand (COD). Analytical results confirmed >۸۵% hardness removal, permeate TDS < ۵۰۰ mg/L, and selective recovery of NaCl (۶۵%), MgSO₄ (۲۰%), Li (۱۰%), and Br⁻ (۵%). The environmental assessment revealed a ۹۰% reduction in brine discharge potential and a ۳۵% decrease in the system’s carbon footprint compared to conventional RO operations. Economic evaluation showed a daily net profit of about ۴۵۰ USD from recovered salts and minerals, highlighting both ecological and financial feasibility. This work represents one of the first semi-industrial demonstrations of sustainable brine management and resource recovery in Iran, providing a replicable model for large-scale applications.

کلیدواژه ها:

RO ، ZLD ، Brine ، Lithium ، Petrochemical Wastewater